The field of the disclosure relates generally to gas turbine engines and, more particularly, methods and systems for improving turbine blade performance with turbine blade winglets.
Many known gas turbine engines have a ducted fan and a core engine arranged in serial flow communication. The fan provides air to the core engine (a “core flow”) and to a bypass duct surrounding the core engine (a “bypass flow”). The core engine compresses the core flow and subsequently mixes it with fuel for igniting the mixture to generate a flow of combustion gas through a turbine. The combustion gas drives the turbine within a cylindrical structure known as a “stationary shroud.” A gap exists between a tip of rotating blades of the turbine and the stationary shroud. Combustion gas leaks over the blade tips from a pressure side of each blade to a suction side of the blade. This leakage rolls up into a vortex on the suction side, contributing to pressure loss and a reduction in blade loading, which reduces turbine efficiency and performance. The tip vortex may also increase secondary pressure losses associated with an upstream shroud purge flow.
Some systems have attempted to reduce these effects using tip flares or other geometrical features to enhance tip sealing characteristics. However, these attempts generally focus on the pressure side of the blade, which does not address losses from vortex roll-up on the suction side of the blade, and have not successfully inhibited vortex development and associated pressure loss.